Francesc Alted wrote:
> Maybe what you are after is to personalize the behaviour of the `atexit`
> hook when exiting PyTables. See at:
>
> http://pytables.org/moin/UserDocuments/AtexitHooks
>
> and tell me if this helps.
I don't think it will for two reasons, one serious, the other minor.
1. We can easily open a lot of files as the programs run, say 2000 or
so. We may only be using 1/500th of that. (Roughly we have file for
each type of data for each day, going over at least two years, and
roughly estimating using four at a time.) I'd like to keep the number
open at any one time small. And I still don't know when PyTables
objects disappear from the caches.
2. Sometimes clients may want to use PyTables directly to open other
files, so changing the defaults to suit my purposes seems improper.
My problem boils down to this, when the weakref dies, the callback is
called before the node is finalized. So if I close the file, the node
finalization leads to errors. My current stumbling block is something
after my callback finishes that tries to access file.root._v__objectID.
file.root is gone, so that throws an error. Any ideas? (And can
going down this road possibly lead to problems where the last changes
aren't flushed to disk?)
The other possible solutions are (1) to either only check my caches
occasionally, and if the weakrefs are all invalid, then close the file
or (2) try to push the closing of the files to a separate thread, which
is much more complicated, but doable.
--
Anthony Foglia
Princeton Consultants
(609) 987-8787 x233
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